Effect of Oral Branched-Chain Amino Acids on Serum Albumin Concentration in Heart Failure Patients with Hypoalbuminemia: Results of a Preliminary Study.

BACKGROUND: We conducted a randomized, controlled trial to determine whether supplementation with oral branched-chain amino acids (BCAAs) improves serum albumin and clinical outcomes in heart failure (HF) patients with hypoalbuminemia. METHODS AND RESULTS: We randomly assigned 18 in-hospital HF patients with serum albumin < 3.5 g/dL to receive oral BCAA granules (LIVACT®) for 28 days during their hospital stay or until discharge (BCAA group; N = 9) or to receive no supplementation (controls; N = 9), in addition to recommended HF therapy. The primary endpoints were changes from baseline in serum albumin and cardiothoracic ratio (CTR). Sixteen patients completed the study. The mean (± standard deviation) period of BCAA supplementation was 18.4 ± 8.4 days. Serum albumin significantly increased in the BCAA group [mean difference vs baseline, 0.44 g/dL; 95% confidence interval (CI) 0.13-0.76; P = 0.014] and did not change in controls (0.18 g/dL; 95% CI - 0.05 to 0.40; P = 0.108). CTR significantly decreased in the BCAA group (- 2.3%; 95% CI - 3.8 to - 0.8; P = 0.014) and did not change in controls (- 1.0%; 95% CI - 2.3 to 0.3; P = 0.111). CONCLUSION: In-hospital HF patients with hypoalbuminemia supplemented with BCAAs showed increased serum albumin and decreased CTR. Clinical trial registration number UMIN000004488 [ http://www.umin.ac.jp/ctr/index.htm ].

Comparative analyses of the cholinergic locus of ChAT and VAChT and its expression in the silkworm Bombyx mori.

The cholinergic locus, which encodes choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT), is specifically expressed in cholinergic neurons, maintaining the cholinergic phenotype. The organization of the locus is conserved in Bilateria. Here we examined the structure of cholinergic locus and cDNA coding for ChAT and VAChT in the silkworm, Bombyx mori. The B. mori ChAT (BmChAT) cDNA encodes a deduced polypeptide including a putative choline/carnitine O-acyltransferase domain and a conserved His residue required for catalysis. The B. mori VAChT (BmVAChT) cDNA encodes a polypeptide including a putative major facilitator superfamily domain and 10 putative transmembrane domains. BmChAT and BmVAChT cDNAs share the 5'-region corresponding to the first and second exon of cholinergic locus. Polymerase chain reaction analyses revealed that BmChAT and BmVAChT mRNAs were specifically expressed in the brain and segmental ganglia. The expression of BmChAT was detected 3 days after oviposition. The expression level was almost constant during the larval stage, decreased in the early pupal stage, and increased toward eclosion. The average ratios of BmChAT mRNA to BmVAChT mRNA in brain-subesophageal ganglion complexes were 0.54±0.10 in the larvae and 1.92±0.11 in adults. In addition, we examined promoter activity of the cholinergic locus and localization of cholinergic neurons, using a baculovirus-mediated gene transfer system. The promoter sequence, located 2kb upstream from the start of transcription, was essential for cholinergic neuron-specific gene õexpression. Cholinergic neurons were found in several regions of the brain and segmental ganglia in the larvae and pharate adults.

Continuous inhibition of poly(ADP-ribose) polymerase does not reduce reperfusion injury in isolated rat heart.

Poly(ADP-ribose) polymerase (PARP), an enzyme that is important to the regulation of nuclear function, is activated by DNA strand breakage. In massive DNA damage, PARP is overactivated, exhausting nicotinamide adenine dinucleotide and leading to cell death. Recent studies have succeeded in reducing cellular damage in ischemia/reperfusion by inhibiting PARP. However, PARP plays an important part in the DNA repair system, and its inhibition may be hazardous in certain situations. We compared the short-time inhibition of PARP against continuous inhibition during ischemia/reperfusion using isolated rat hearts. The hearts were reperfused after 21 minutes of ischemia with a bolus injection of 3-aminobenzamide (3-AB) (10 mg/kg) followed by continuous 3-AB infusion (50 µM) for the whole reperfusion period or for the first 6 minutes or without 3-AB. At the end of reperfusion, contractile function, high-energy phosphate content, nicotinamide adenine dinucleotide content, and infarcted area were significantly preserved in the 3-AB 6-minute group. In the 3-AB continuous group, these advantages were not apparent. At the end of reperfusion, PARP cleavage had significantly proceeded in the 3-AB continuous group, indicating initiation of the apoptotic cascade. Thus, continuous PARP inhibition by 3-AB does not reduce reperfusion injury in the isolated rat heart, which may be because of acceleration of apoptosis.

Carbon monoxide from heme oxygenase-2 Is a tonic regulator against NO-dependent vasodilatation in the adult rat cerebral microcirculation.

Although the brain generates NO and carbon monoxide (CO), it is unknown how these gases and their enzyme systems interact with each other to regulate cerebrovascular function. We examined whether CO produced by heme oxygenase (HO) modulates generation and action of constitutive NO in the rat pial microcirculation. Immunohistochemical analyses indicated that HO-2 occurred in neurons and arachnoid trabecular cells, where NO synthase 1 (NOS1) was detectable, and also in vascular endothelium-expressing NOS3, suggesting colocalization of CO- and NO-generating sites. Intravital microscopy using a closed cranial window preparation revealed that blockade of the HO activity by zinc protoporphyrin IX significantly dilates arterioles. This vasodilatation depended on local NOS activities and was abolished by CO supplementation, suggesting that the gas derived from HO-2 tonically regulates NO-mediated vasodilatory response. Bioimaging of NO by laser-confocal microfluorography of diaminofluorescein indicated detectable amounts of NO at the microvascular wall, the subdural mesothelial cells, and arachnoid trabecular cells, which express NOS in and around the pial microvasculature. On CO inhibition by the HO inhibitor, regional NO formation was augmented in these cells. Such a pattern of accelerated NO formation depended on NOS activities and was again attenuated by the local CO supplementation. Studies using cultured porcine aortic endothelial cells suggested that the inhibitory action of CO on NOS could result from the photo-reversible gas binding to the prosthetic heme. Collectively, CO derived from HO-2 appears to serve as a tonic vasoregulator antagonizing NO-mediated vasodilatation in the rat cerebral microcirculation.

Statins inhibit beta-adrenergic receptor-stimulated apoptosis in adult rat ventricular myocytes via a Rac1-dependent mechanism.

BACKGROUND: 3-hydroxy-3-methylglutaryl coenzyme A inhibitors (statins) inhibit myocyte hypertrophy in vitro and ameliorate the progression of cardiac remodeling in vivo, possibly because of inhibition of the small GTPase Rac1. The role of Rac1 in mediating myocyte apoptosis is not known. beta-Adrenergic receptor (betaAR)-stimulated myocyte apoptosis is mediated via activation of c-Jun NH2-terminal kinase (JNK), leading to activation of the mitochondrial death pathway. We hypothesized that betaAR-stimulated apoptosis in adult rat ventricular myocyte (ARVMs) is mediated by Rac1 and inhibited by statins. METHODS AND RESULTS: betaAR stimulation increased apoptosis, as assessed by transferase-mediated nick-end labeling, from 5+/-1% to 24+/-2%. betaAR stimulation also increased Rac1 activity. Adenoviral overexpression of a dominant-negative mutant of Rac1 inhibited betaAR-stimulated apoptosis, JNK activation, cytochrome C release, and caspase-3 activation. Cerivastatin likewise inhibited the betaAR-stimulated activation of Rac1, decreased betaAR-stimulated apoptosis to 11+/-2%, and inhibited JNK activation, cytochrome C release, and caspase-3 activation. CONCLUSIONS: betaAR stimulation causes Rac1 activation, which is required for myocyte apoptosis and leads to activation of JNK and the mitochondrial death pathway. Cerivastatin inhibits betaAR-stimulated activation of Rac1 and thereby inhibits JNK-dependent activation of the mitochondrial death pathway and apoptosis. The beneficial effects of statins on the myocardium may be mediated in part via inhibition of Rac1-dependent myocyte apoptosis.